Where did all the space on my hard drive go?

[kjw]

Am I missing something major here?

When I highlight the contents of the C drive in Explorer and click properties, it says there is 61.1 Gb used.

When I click properties for the C drive under Computer, it says 99.9 Gb are being used.

Why the big difference? Where did the other 38.8 Gb go?

(Karen's Disk Slack Checker says 80 Gb is being used.)

Any thoughts on what is going on and/or how to fix it or recover that space?

Thanks much for your help and time!!

[catgate]

It is a shambles. The way this is reported is not helpful and like a lot more in computing it is all confused by the jargon.

Trying to explain it without jargon is not easy, but..... When files are stored they are not always stored in one "contiguous" chunk i.e continuous block. That is the prefered way, but sometimes this is not possible. because there may not be, at the time, a convenient space, so it is split up, and the location of these bits is recorded, so as to be able to retrieve them. The small unsed bits of space between big used blocks is looked upon as "slack". The move to 64 bit from 32bit has made this situation worse. So it is thus possible to have more space unavailable than the figure given by subtracting the amount of known stored data from the quoted total disc space.

I do not know if "defragging" forms part of the capability of Vista, but this was one of the things that was done to cure the results of file fragmentation in earlier M$ OSs

Then there is the matter of hidden files and partitions, if any.

[ɹəuəllıʍ ʇɐb]

I don't know what that left panel is in your image; it says PerfLogs - I think you can just ignore it. The right panel shows the correct sizes.

[Dencandy]

This is a Vista specific problem explained ON THIS FORUM. The PerfLog menu only includes performance & monitoring files, the other menu measures the total amount of available and used hard disk space. I see that you do not have drive compression enabled. Given that you have a relatively low amount of space available, enabling file compression would eliminate most of the slack space catgate refers to in his post. "Slack" is, basically, unused space within a disk sector which cannot be used to store any other data except additions to the file associated with that sector. If you have a lot of small files stored your slack (unusable space) can easily exceed the total used space. Defragmenting cannot eliminate slack, only compression can. What drive compression does is to place everything on the hard disk into a single huge file with no slack thus freeing up more space.

The results you show from Karen's Disk Slack Checker (which I don't use) indicates that the difference between the MS figure of 99.9GB & Karen's figure of 80GB (i.e. 10.9GB) is the total amount of slack that you could save by using full drive compression.

Try initiating compression and see if you get much extra space. You can also compress individual large folders into compressed files by right clicking and selecting "Send to.. compressed file". If you don't like the results you easily undo compression, there's no risk of losing data.

You may notice a slight increase in the time it takes to access a compressed drive or folder but that can be compensated for by using the Indexing Sevice (which you already use). But if lack of space on your hard disk is becoming a problem, file compression might help. You could also think about purging some of your old files & little-used programs to save space. Many of us on this forum also use CCleaner to find & remove bits of old programs & unused data & records. You can get it here: CCLEANER, but take the tour first to find out how it works.

[kjw]

Thanks for the help! I will look into your suggestions.

(Regarding the "perflog" part, that just happened to be the folder I was over when I highlighted the contents of the C drive and right clicked prior to "properties". If I had had the cursor over the "windows" folder, you would have seen "windows" instead of perflog -- but the number was the size of all the folders added up, not just the perflog folder.)